Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
There is known an image reading apparatus that can read a document by two kinds of methods: the method that reads a document placed on a platen constituted of a transparent member such as glass; and the method that reads a document by conveying the document, which is placed on a document placement table, to the platen. There is known a technique that, by locating a sensor that detects a size of a document placed, for example, on a platen and a document placement table, determines the size of the document detected by the sensor as a read size of the document when a user has not operated to determine the read size (the size of the document to be read) of the document.